Electronic device including an organic active layer and process for forming the electronic device

ABSTRACT

An electronic device can include an organic active layer and an electrode. In one aspect, the electrode can further include a first layer that is conductive, and a second layer that is conductive. The second layer can include a defect extending at least partly through a thickness of the second conductive layer. The electrode can also include a third layer lying within and substantially filling the defect, wherein each of the second and third layers includes a same metallic element. In another aspect, a process for forming an electronic device can include forming an organic active layer and forming a first layer that is conductive and is part of an electrode. The process can also include forming a second layer and exposing the second layer to a first plasma to form a first compound from the second layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119(e)from provisional U.S. Application No. 60/753,516, “Electronic DeviceIncluding an Organic Active Layer and Process for Forming the ElectronicDevice”, Ramakrishnan, et al, filed Dec. 23, 2005, which is incorporatedherein by reference in its entirety.

BACKGROUND INFORMATION

1. Field of the Disclosure

The invention relates generally to electronic devices and, morespecifically, to electronic devices including organic active materialsand processes for forming the same.

2. Description of the Related Art

Electronic devices, including organic electronic devices, continue to bemore extensively used in everyday life. Examples of an organicelectronic device can include an Organic Light-Emitting Diode (“OLED”).A low work function material can be used as a part of an electrode ofthe OLED. An example of a low work function material can be a Group 1 orGroup 2 metal, or any combination thereof. Such a material can reactwith moisture if not properly sealed. Such a reaction can render theelectronic device unusable.

One approach to fabricating an electrode with a low work function can beto form the electrode with two layers. A first layer of the electrodecontaining the low work function material can be closer to an organicactive layer of the device, and a second layer of the electrode acts asa conductor and helps prevent the first layer from contacting moisture.Radiation at a targeted wavelength or in a targeted spectrum may need topass through the electrode in a particular application. However, ifradiation at a targeted wavelength or in a targeted spectrum is to passthrough the electrode using the two-layer approach, the second layer ofthe electrode may not have a sufficient thickness to prevent moisturefrom reaching the first layer of the electrode. A defect extending atleast partly through the second layer may cause premature failure of theelectronic device.

SUMMARY

An electronic device can include an organic active layer and anelectrode. In one aspect, the electrode can further include a firstlayer that is conductive, and a second layer that is conductive. Thesecond layer can include a defect extending at least partly through athickness of the second conductive layer. The electrode can also includea third layer lying within and substantially filling the defect, whereineach of the second and third layers includes a same metallic element.

In another aspect, a process for forming an electronic device caninclude forming an organic active layer and forming a first layer thatis conductive and is part of an electrode. The process can also includeforming a second layer and exposing the second layer to a first plasmato form a first compound from the second layer. In one embodiment,substantially all of the second layer can be consumed when forming thefirst compound.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated in the accompanying figures to improveunderstanding of concepts as presented herein.

FIG. 1 includes an illustration of a workpiece with first electrodes andconductive members overlying a substrate.

FIG. 2 includes an illustration of the workpiece of FIG. 1 after formingan organic layer.

FIG. 3 includes an illustration of the workpiece of FIG. 2 after forminga first conducting layer and a second conducting layer of an electrode,wherein the second layer has a defect.

FIG. 4 includes an illustration of the workpiece of FIG. 3 after formingof a third layer.

FIG. 5 includes an illustration of a substantially completed electronicdevice.

FIG. 6 includes an illustration of the workpiece of FIG. 4 after formingan additional conducting layer in accordance with an alternateembodiment.

FIG. 7 includes an illustration of the workpiece of FIG. 6 aftersubstantially all of the additional conducting layer forms a compound.

Skilled artisans appreciate that objects in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the objects in the figures may beexaggerated relative to other objects to help to improve understandingof embodiments.

DETAILED DESCRIPTION

In a first aspect, an electronic device can include an organic activelayer, and an electrode. The electrode can further include a first layerthat is conductive, and a second layer that is conductive. The secondlayer can include a defect extending at least partly through a thicknessof the second conductive layer, and the electrode can also include athird layer lying within and substantially filling the defect, whereineach of the second and third layers include a same metallic element.

In an embodiment of the first aspect, the electronic device can furtherinclude another electrode wherein the organic active layer lies betweenthe electrodes. In another embodiment, the first conductive layerincludes a Group 1 metal, a Group 2 metal, or any combination thereof.In still another embodiment, the second conductive layer includesaluminum, silver, copper, chromium or any combination thereof.

In yet another embodiment, the third layer includes anitrogen-containing, oxygen-containing, fluorine-containing or anycombination thereof material. In another embodiment of the first aspect,the electrode can further include a fourth layer overlying the thirdlayer, the fourth layer including a metal-oxide compound, ametal-nitride compound, a metal-fluoride compound or any combinationthereof.

In a second aspect, a process for forming an electronic device caninclude forming an organic active layer, and forming an electrodefurther including a first layer and a second layer. Each of the firstand second layers is conductive, the second layer is a last layer formedwhen forming the electrode, and the second layer includes a defectextending at least partly through a thickness of the second layer. Theprocess can further include exposing the second layer to a plasma toform a compound in the defect, wherein the compound is formed from aportion of the second layer.

In a n embodiment of the second aspect, forming the organic active layerincludes continuously printing the organic active layer. In anotherembodiment forming the electrode further includes forming each of thefirst and second layers of the electrode using a physical vapordeposition process. In still another embodiment, forming the electrodefurther includes forming each of the first and second layers of theelectrode using a same stencil mask.

In a particular embodiment of the second aspect, the plasma includesoxygen, nitrogen, fluorine, argon, helium, another noble gas, or anycombination thereof. In a more particular embodiment, the plasma of theplasma treatment process is formed in a nitrogen-containing,oxygen-containing, fluorine-containing or any combination thereofambient.

In a third aspect, a process for forming an electronic device caninclude forming an organic active layer, and forming a first layer thatis conductive and is part of an electrode. The process can furtherinclude forming a second layer, and exposing the second layer to a firstplasma to form a first compound from the second layer, whereinsubstantially all of the second layer is consumed when forming the firstcompound.

In an embodiment of the third aspect, the first plasma includesnitrogen, oxygen, fluorine, argon, helium, another noble gas, or anycombination thereof. In another embodiment, each of the first and secondlayers includes a metal-containing material.

In a particular embodiment of the third aspect, the process can furtherinclude forming a third layer after forming the first layer and beforeforming the second layer, wherein the third layer is conductive and ispart of the electrode. In a more particular embodiment, the process canfurther include forming a fourth layer after exposing the second layerto the first plasma. In an even more particular embodiment, the fourthlayer includes a metal-containing layer. In a still more particularembodiment the process can further include exposing the fourth layer toa second plasma to form a second compound from the fourth layer, whereinsubstantially all of the fourth layer is consumed when forming thesecond compound.

In an embodiment of the third aspect, forming the second layer includesdepositing a material including aluminum, tantalum, niobium, titanium,zirconium, hafnium, nickel, cobalt, chromium, molybdenum, tungsten,lanthanum, cerium, another rare earth metal, indium, tin, zinc, an alloyof titanium and zirconium, indium and tin, indium and zinc, aluminum andzinc or any combination thereof.

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments willbe apparent from the following detailed description, and from theclaims. The detailed description first addresses Definitions andClarification of Terms followed by Partial Formation of the Device,Including Formation of the Organic Active Layer, Formation of the SecondElectrode, Formation of Encapsulation, Alternate Embodiments, Benefits,and finally Examples.

1. Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms aredefined or clarified.

The terms “array,” “peripheral circuitry,” and “remote circuitry” areintended to mean different areas or components of an electronic device.For example, an array may include pixels, cells, or other structureswithin an orderly arrangement (usually designated by columns and rows).The pixels, cells, or other structures within the array may becontrolled by peripheral circuitry, which may lie on the same substrateas the array but outside the array itself. Remote circuitry typicallylies away from the peripheral circuitry and can send signals to orreceive signals from the array (typically via the peripheral circuitry).The remote circuitry may also perform functions unrelated to the array.The remote circuitry may or may not reside on the substrate having thearray.

The term “conductive,” when referring to a layer, material, member, orstructure is intended to mean such a layer, material, member, orstructure through which a significant number of charge carriers (e.g.,electrons, holes, or a combination thereof) may pass when operating anelectronic device, including such layer, material, member, or structure,over a range of normal operating voltages (e.g., a designed voltagerange for use by an end user of the electronic device). In oneembodiment, a conductive material has a bulk resistivity no greater thanapproximately 10⁺² ohm-cm.

The term “continuous” and its variants are intended to meansubstantially unbroken. In one embodiment, continuously printing isprinting using a substantially unbroken stream of a liquid or a liquidcomposition, as opposed to a depositing technique using drops. Inanother embodiment, extending continuously refers to a length of alayer, member, or structure in which no significant breaks in the layer,member, or structure lie along its length.

The term “defect” is intended to mean an unintended artifact in a layer,member, or structure, wherein such artifact is formed before anelectronic device, including such layer, member, or structure, issubstantially completed. In one embodiment, the defect may extend adistance into a layer, member, or structure, wherein the distance issignificantly larger than the root mean square roughness of a surface ofsuch layer, member, or structure from which such defect extends. Apinhole extending through at least most of a layer is an example of adefect. An opening formed within a layer, member, or structure by use ofa stencil mask or other lithographic process is not a defect.

The term “electrode” is intended to mean a member, a structure, or acombination thereof configured to transport carriers within anelectronic component. For example, an electrode may be an anode, acathode, a capacitor electrode, a gate electrode, etc. An electrode mayinclude a part of a transistor, a capacitor, a resistor, an inductor, adiode, an electronic component, a power supply, or any combinationthereof.

The term “electronic component” is intended to mean a lowest level unitof a circuit that performs an electrical or electro-radiative (e.g.,electro-optic) function. An electronic component may include atransistor, a diode, a resistor, a capacitor, an inductor, asemiconductor laser, an optical switch, or the like. An electroniccomponent does not include parasitic resistance (e.g., resistance of awire) or parasitic capacitance (e.g., capacitive coupling between twoconductors electrically connected to different electronic componentswhere a capacitor between the conductors is unintended or incidental).

The term “electronic device” is intended to mean a collection ofcircuits, electronic components, or combinations thereof thatcollectively, when properly electrically connected and supplied with theappropriate potential(s), performs a function. An electronic device mayinclude or be part of a system. An example of an electronic deviceincludes a display, a sensor array, a computer system, an avionicssystem, an automobile, a cellular phone, other consumer or industrialelectronic product, or any combination thereof.

The term “elevation” is intended to mean a distance from a primarysurface of a substrate as measured in a direction perpendicular to theprimary surface.

The term “metallic” is intended to mean containing one or more metals.For example, a metallic coating can include an elemental metal byitself, a clad, an alloy, a plurality of layers of any combination ofelemental metal(s), clad(s), alloy(s), or any combination thereof.

The term “organic active layer” is intended to mean one or more organiclayers, wherein at least one of the organic layers, by itself, or whenin contact with a dissimilar material is capable of forming a rectifyingjunction.

The term “organic layer” is intended to mean one or more layers, whereinat least one of the layers comprises a material including carbon and atleast one other element, such as hydrogen, oxygen, nitrogen, fluorine,etc.

The term “physical vapor deposition” is intended to mean a process bywhich material is condensed from a vapor state to form a solid film on asubstrate. Evaporation and sputtering are both examples of physicalvapor deposition processes.

The term “plasma” is intended to mean an at least partially ionized gasformed by an electrical field. The plasma may include negatively chargedspecies, positively charged species, neutral species, or any combinationthereof.

The term “primary surface” is intended to mean a surface of a substratefrom which an electronic component is subsequently formed.

The term “radiation-emitting component” is intended to mean anelectronic component, which when properly biased, emits radiation at atargeted wavelength or spectrum of wavelengths. The radiation may bewithin the visible-light spectrum or outside the visible-light spectrum(UV or IR). A light-emitting diode is an example of a radiation-emittingcomponent.

The term “radiation-responsive component” is intended to mean anelectronic component, which when properly biased, can respond toradiation at a targeted wavelength or spectrum of wavelengths. Theradiation may be within the visible-light spectrum or outside thevisible-light spectrum (UV or IR). An IR sensor and a photovoltaic cellare examples of radiation-sensing components.

The term “rectifying junction” is intended to mean a junction within asemiconductor layer or a junction formed by an interface between asemiconductor layer and a dissimilar material, in which charge carriersof one type flow easier in one direction through the junction comparedto the opposite direction. A pn junction is an example of a rectifyingjunction that can be used as a diode.

The term “stencil mask” is intended to mean an object including apattern having one or more openings that allows a corresponding patternto be formed over or within a substrate. A shadow mask is a specifictype of stencil mask that can be used to deposit one or more materialsover a substrate substantially only at one or more areas correspondingto one of more openings within such mask. A lithographic mask is anotherspecific type of stencil mask that can be used to pattern a resistlayer. The lithographic mask includes a pattern of opaque features orother radiation attenuators and may or may not have a mask substrate(e.g., a quartz plate) substantially transparent to radiation used whenpatterning with the lithographic mask.

The term “substrate” is intended to mean a workpiece that can be eitherrigid or flexible and may include one or more layers of one or morematerials, which can include, but are not limited to, glass, polymer,metal or ceramic materials or combinations thereof.

The term “visible light spectrum” is intended to mean a radiationspectrum having wavelengths corresponding to 400 to 700 nm.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of theelements use the “New Notation” convention as seen in the CRC Handbookof Chemistry and Physics, 81^(st) Edition (2000-2001).

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

To the extent not described herein, many details regarding specificmaterials, processing acts, and circuits are conventional and may befound in textbooks and other sources within the organic light-emittingdiode display, photodetector, photovoltaic, and semiconductive memberarts.

2. Partial Formation of the Device, Including Formation of the OrganicActive Layer

FIG. 1 includes an illustration of a cross-sectional view of a portionof a workpiece 10 including first electrodes 18 and a substrate 12. Thesubstrate 12 can be either rigid or flexible and may include one or morelayers of one or more materials, which can include, but are not limitedto, glass, polymer, metal or ceramic materials or combinations thereof.In one embodiment, the substrate 12 is substantially transparent to atargeted wavelength or spectrum of wavelengths associated with theelectronic device. For example, the electronic device may emit radiationwithin the visible light spectrum, and thus, the substrate 12 would betransparent to radiation within the visible light spectrum. In anotherexample, the electronic device may respond to infrared radiation, andthus the substrate 12 would be transparent to the infrared radiation.The substrate 12 can have a thickness in a range of approximately 12 to2500 microns.

The substrate 12 includes a user surface 14 and a primary surface 16.The user surface 14 can be the surface of the substrate 12 seen by auser when using the electronic device. The primary surface 16 can be asurface from which at least some of electronic components for theelectronic device may be fabricated. Although not illustrated, controlcircuits may lie within substrate 12, wherein each control circuit wouldbe electrically connected to a corresponding first electrode 18.

A conductive layer can be formed over the substrate 12 and portions canbe removed by a conventional or proprietary technique to form the firstelectrodes 18 and conductive portions 112 of conductive members 110. Inone embodiment, the first electrodes 18 can act as anodes for electroniccomponents and include one or more layers used as anodes within LCD orOLED displays. The first electrodes 18 can be formed by a depositionusing a conventional or proprietary technique. The first electrodes 18may have a thickness in a range of approximately 10 to 1000 nm.

The conductive members 110 can act as part of a ground connection forelectronic components of the electronic device. In one embodiment, theconductive members 110 are substantially complete after forming theconductive portions 112. In the illustrated embodiment, conventional orproprietary deposition and optional, separate patterning techniques canbe used to form conductive portions 114 overlying conductive portions112 to substantially complete the conductive members 110. The conductiveportions 114 can have a thickness in a range of approximately 10 to 1000nm and can comprise a conductive material such as a metal, a metalalloy, a conductive metal oxide, a conductive metal nitride, aconductive metal oxynitride, a conductive organic material, or one ormore other suitable materials, or any combination thereof, as describedherein. The conductive portions 112 and 114 may include the same ordifferent materials. In a particular embodiment, conductive portion 114can comprise a stack of Cr/Al/Cr layers and have a total thickness in arange of 500 to 600 nm.

An organic layer 22 is formed over the first electrodes 18 and thesubstrate 12, as illustrated in FIG. 2. The organic layer 22 may includeone or more layers. For example, the organic layer can include anorganic active layer, a buffer layer, an electron-injection layer, anelectron-transport layer, an electron-blocking layer, a hole-injectionlayer, a hole-transport layer, or a hole-blocking layer, or anycombination thereof. In one embodiment, the organic layer 22 may includea first organic layer 24 and an organic active layer 26.

Any individual or combination of layers within the organic layer 22 canbe formed by a conventional or proprietary technique, including spincoating, vapor depositing (chemical or physical), printing (ink jetprinting, screen printing, solution dispensing (dispensing the liquidcomposition in strips or other predetermined geometric shapes orpatterns, as seen from a plan view), another continuous printing processor any combination thereof, other depositing techniques, or anycombination thereof for appropriate materials as described below. Anyindividual or combination of layers within the organic layer 22 may becured after deposition.

As illustrated in FIG. 2, the first organic layer 24 may act as a bufferlayer, an electron-blocking layer, a hole-injection layer, ahole-transport layer, or any combination thereof. In one embodiment, thefirst organic layer includes a single layer, and in another embodiment,the first organic layer 24 can include a plurality of layers. The firstorganic layer 24 may include one or more materials that may be selecteddepending on the function that the first organic layer 24 is to provide.In one embodiment, if the first organic layer 24 is to act as a bufferlayer, the first organic layer 24 may include a conventional orproprietary material that is suitable for use in a buffer layer, as usedin an OLED display. In another embodiment, if the first organic layer 24is to act as a hole-transport layer, the first organic layer may includea conventional or proprietary material that is suitable for use in ahole-transport layer. In one embodiment, the thickness of the firstorganic layer 24 may have a thickness in a range of approximately 50 to300 nm, as measured over the substrate 12 at a location spaced apartfrom the first electrodes 18. In another embodiment, the first organiclayer 24 may be thinner or thicker than the range recited above.

The composition of the organic active layer 26 can depend upon theapplication of the electronic device. In one embodiment, the organicactive layer 26 is used in a radiation-emitting component. In aparticular embodiment, the organic active layer 26 can include a bluelight-emitting material, a green light-emitting material, or a redlight-emitting material. Other organic active layers (not illustrated)for radiation at different targeted wavelengths or spectra ofwavelengths, as compared to the organic active layer 26, can be formed.Although not illustrated, a structure (e.g., a well structure, cathodeseparators, or the like) may lie adjacent the first electrodes 18 toreduce the likelihood of materials from different organic active layersfrom contacting each other at locations above the first electrodes 18.For a monochromatic display, the organic active layers may havesubstantially the same composition. In another embodiment, an organicactive layer that is substantially continuous over the portion of thesubstrate 12 illustrated in FIG. 2 can replace the organic active layer26. In another embodiment, the organic active layer 26 may be used in aradiation-responsive component, such as a radiation sensor, photovoltaiccell, or the like.

The organic active layer 26 and potentially other organic active layerscan include material(s) conventionally used as organic active layers inorganic electronic devices and can include one or more small moleculematerials, one or more polymer materials, or any combination thereof.After reading this specification, skilled artisans will be capable ofselecting appropriate material(s), layer(s) or both for the organicactive layer 26 or potentially other organic active layers. In oneembodiment, the organic active layers 26 or another potential organicactive layer has a thickness in a range of approximately 40 to 100 nm,and in a more specific embodiment, in a range of approximately 70 to 90nm. In one embodiment, organic active layer 26 can be formed by acontinuous printing process.

In an alternative embodiment, the organic layer 22 may include a singlelayer with a composition that varies with thickness. For example, thecomposition nearest the first electrodes 18 may act as a holetransporter, the next composition may act as an organic active layer,and the composition furthest from the first electrodes 18 may act as anelectron transporter. Similarly, the function of charge injection,charge blocking, or any combination of charge injection, chargetransport, and charge blocking can be incorporated into the organiclayer 22. One or more materials may be present throughout all or onlypart of the thickness of the organic layer.

Although not illustrated, a hole-blocking layer, an electron injectionlayer, an electron-transport layer, or any combination thereof may bepart of the organic layer 22 and formed over the organic active layer26. The electron-transport layer can allow electrons to be injected fromthe subsequently formed second electrode (i.e., cathode) and transferredto the organic active layer 26. The hole-blocking layer, electroninjection layer, electron-transport layer, or any combination thereoftypically has a thickness in a range of approximately 30 to 500 nm.

Any one or more of the layers within the organic layer 22 may bepatterned using a conventional or proprietary technique to removeportions of the organic layer 22 where electrical contacts (notillustrated) are subsequently made. Typically, the electrical contactareas are near the edge of the array or outside the array to allowperipheral circuitry to send or receive signals to or from the array.

3. Formation of the Second Electrode

A second electrode 32 is formed over the organic layer 22, such that theorganic active layer 26 lies between the first electrodes 18 and thesecond electrode 32, as illustrated in FIG. 3. The second electrode 32can act as a cathode for the electronic component being formed. In oneembodiment, the electronic component is a radiation-emitting component,a radiation-responsive component, or the like. In a further embodiment(not illustrated), a path to a different user surface of the electronicdevice can pass through the second electrode and may limit the possiblethickness range for the second electrode 32.

The second electrode 32 can include one or more layers or otherportions. A layer or portion of the second electrode 32 closest to theorganic active layer 26 can set the work function for the secondelectrode 32. In one embodiment, another layer or portion of the secondelectrode 32 can be used to help isolate the work function settingportion from one or more contaminants, such as moisture, while allowingcurrent to flow at relatively low resistance. In a particular embodimentas illustrated in FIG. 3, the second electrode 32 includes a firstconductive layer 34 and a second conductive layer 36. As illustrated,the second conductive layer 36 includes a defect 38.

The first conductive layer 34 can include a low work function material.The first conductive layer 34 can include a Group 1 metal (e.g., Li, Cs,etc.), a Group 2 (alkaline earth) metal, a rare earth metal, includingthe lanthanides and the actinides, an alloy including any of theforegoing metals, a salt of any of the foregoing, or any combinationthereof. A conductive polymer with a low work function may also be used.The thickness of the first conductive layer 34 can be in a range ofapproximately 0.5 to 5 nm. In one embodiment, the thickness of the firstconductive layer 34 is chosen such that the first conductive layer 34 issubstantially transparent to radiation at the targeted wavelength orspectrum of wavelengths. In another embodiment, the first conductivelayer 34 can have a thickness outside of the range (thinner or thicker).

The second conductive layer 36 may include nearly any conductivematerial, including those previously described with respect to the firstelectrodes 18. The second conductive layer 36 is used primarily for itsability to allow current to flow while keeping resistance relatively lowbut can also help reduce the interaction of material from the firstconductive layer 34 with the atmosphere. Second conductive layer 36 cancomprise the last layer of second electrode 32. At least a potion oflayer 36 can contain a metal element. An exemplary material for secondconductive layer 36 includes aluminum, silver, copper, or anycombination thereof. In many applications, the thickness of the secondconductive layer 36 may be in a range of approximately 5 to 500 nm. Ifradiation is not to be transmitted through the second electrode 32, theupper limit on the thickness of the second conductive layer 36 may begreater than 500 nm.

In one embodiment, the second electrode 32 is formed by placing astencil mask over the substrate 12 and using a conventional orproprietary physical vapor deposition technique to deposit firstconductive layer 34 and second conductive layer 36 of second electrode32, as illustrated in FIG. 3. In another embodiment, the secondelectrode 32 is formed by blanket depositing any individual orcombination of the layers 34 and 36 for the second electrode 32. Amasking layer (not illustrated) is then formed over portions of thelayer(s) that are to remain to form second electrode 32. A conventionalor proprietary etching technique is used to remove exposed portions ofthe layer(s) and leave the second electrode 32. After the etching, themasking layer is removed using a conventional or proprietary technique.

During or subsequent to forming the second conductive layer 36, a defect38 can be formed, wherein the second conductive layer 36 is locallythinner at the defect 38 than a nominal thickness of the secondconductive layer 36. A defect 38 can be more likely to affect theelectronic device when the second conductive layer 36 is nominally lessthan 500 nm in thickness than when second conductive layer 36 isnominally 500 nm or greater in thickness, such as when radiation is tobe transmitted through the second electrode 32. In one embodiment, thedefect 38 can extend at least partly into the second conductive layer36. In another embodiment, the defect 38 can extend most of the waythrough a thickness of the second conductive layer 36. In still anotherembodiment, the defect 38 may extend completely through the secondconductive layer 36, and thus allow the first conductive layer 34 tobecome exposed.

The ability of moisture or other contaminants to reach the firstconductive layer 34 can vary across second conductive layer 36. Forexample, it may be less difficult for moisture or contaminants to reachconductive layer 34 at defect 38 than at a location of nominalthickness. Moisture or contaminants reaching conductive layer 34 at alocation can contribute to earlier failure of an electronic componentthat contains the location.

4. Formation of Encapsulation

A third layer 42 can be formed by exposing a portion of the secondconductive layer 36 to a plasma, as illustrated in FIG. 4. The thirdlayer 42 can comprise a metal oxide, a metal nitride, a metal fluoride,or any combination thereof, formed within the defect 38. The portion ofthe third layer 42 within the defect 38 can make it more difficult formoisture or other contaminants to reach the first conductive layer 34than it would be without the third layer 42 present. Thus, formation ofthe third layer 42 within defect 38 can help extend the time to failurefor a portion near defect 38. In one embodiment, the third layer 42 canlie within and at least partially fill the defect 38. In anotherembodiment, the third layer 42 can overlie other portions of the secondconductive layer 36 in addition to lying within the defect 38. Inanother embodiment, the third layer 42 can substantially fill the defect38.

The second conductive layer 36 can be exposed to a plasma treatmentprocess including a first plasma. During the exposure to the firstplasma, a portion of the second conductive layer 36 can react to formthe third layer 42. The third layer 42 can be a first encapsulatinglayer and can include a compound formed from the exposed portion of thesecond conductive layer 36. In a particular embodiment, workpiece 10 canbe placed in an oxygen-containing ambient, nitrogen-containing ambient,fluorine-containing ambient or any combination thereof. The first plasmacan be formed that includes oxygen, nitrogen, fluorine, or anycombination thereof. A surface portion of the second conductive layer 36can react with the first plasma to form an oxygen-containing material,nitrogen-containing material, fluorine-containing material, or anycombination thereof. In one embodiment, a metal-containing portion ofsecond conductive layer 36 can form a metallic oxide portion, a metallicnitride portion, a metallic fluoride portion or any combination thereofof the third layer 42. The third layer 42 may be a conductor or aninsulator.

Other circuitry not illustrated, may be formed using any number of thepreviously described or additional layers. Although not illustrated,additional insulating layer(s) and interconnect level(s) may be formedto allow for circuitry in peripheral areas (not illustrated) that maylie outside the array. Such circuitry may include row or columndecoders, strobes (e.g., row array strobe, column array strobe, or thelike), sense amplifiers, or any combination thereof.

A lid 56 with a desiccant 54 is attached to the substrate 12 atlocations (not illustrated) outside the array to form a substantiallycompleted electronic device. A gap 52 may or may not lie betweenelectrode 32 and the desiccant 54. The materials used for the lid anddesiccant and the attaching process are conventional or proprietary. Thelid 56 typically lies on a side of the electronic device opposite theuser side of the electronic device. Still, if desired, radiation may betransmitted through the lid 56 instead of or in conjunction with thesubstrate 12. If so, the lid 56 and desiccant 54 can be designed toallow sufficient radiation to pass through. In another embodiment, thethird layer 42 provides sufficiently robust encapsulation to allowdesiccant 54 to be omitted.

5. Alternate Embodiments

In an alternate embodiment, where a thicker encapsulation layer isneeded or desired, an additional conductive layer 62 can be depositedoverlying the third layer 42 as illustrated in FIG. 6. Additionalconductive layer 62 can be formed by any embodiment described for secondconductive layer 32. The thickness of additional conductive layer 62 canbe selected such that during exposure to a second plasma substantiallyall of additional conductive layer 62 can be consumed to form acompound. In one embodiment, additional conductive layer 62 is notgreater than 60 nm in thickness.

Additional conductive layer 62 can then be exposed to the second plasmaas illustrated in FIG. 7. The second plasma can be formed in conditionssimilar to the first plasma. Substantially all of additional conductivelayer 62 can be converted to a compound effectively thickening theencapsulation layer 42 to form an encapsulating layer 72. By depositingother additional conductive layers 62 and exposing each to a plasmatreatment, an encapsulation layer 72 of substantially any thickness canbe formed. Although not illustrated, an opening can be made in theencapsulating layer 72 to allow electrical or other contact to theelectrode 32. In other embodiments, the encapsulating layer 72 can beconductive so such an opening may not be formed.

In other embodiments, the electrodes 18 and 32 can be reversed. In thisembodiment, the electrode 32 would lie closer to the user side of thesubstrate 12, as compared to electrodes 18. The electrode 32 couldinclude a plurality of second electrodes that are each connected tocontrol circuits (not illustrated). Also, the first electrodes 18 couldbe replaced by a common first electrode. In still another alternativeembodiment, the control circuits may be connected to one type ofelectrode that lie farther from the substrate 12 as compared to theother type of electrode.

6. Benefits

The defect 38 extending part way or completely through the secondconductive layer 36 can shorten the time to failure for an electronicdevice. Such a defect can be problematic when the second conductivelayer 36 is constrained by its designed maximum thickness. For example,radiation at a targeted wavelength or spectrum may need to be, or bedesigned to be, transmitted through the second electrode 32.

Encapsulating the second electrode 32 after formation of the secondconductive layer 36 can reduce the ability of moisture or othercontaminants to reach the first conductive layer 34 through the defect38 in sufficient quantity to impair the function of the electronicdevice. Improvement in robustness of the second conductive layer 36 canreduce or eliminate the need for a desiccant 54 to be included in thepackage.

EXAMPLE

The concepts described herein will be further described in the followingexample, which does not limit the scope of the invention described inthe claims. The Example demonstrates integration of an encapsulatinglayer into a typical PLED or OLED display manufacturing process.

One or more organic layers, including an organic active layer aredeposited overlying a substrate including an ITO anode. A cathode can beformed over the organic layer(s) and include a first conductive layerand a second conductive layer. The first conductive layer of Ca, Ba, Li,LiF, or Mg—Ag is deposited by either evaporation or sputtering undervacuum. The thickness of the first conductive layer can be in a range ofapproximately 2 to 10 nm. The second conductive layer of Al can bedeposited by evaporating or sputtering under vacuum. The secondconductive layer can have a thickness in a range of 100 nm to 1000 nm.The first and second conductive layers can be deposited using the sameshadow mask.

The surface of the second conductive layer is exposed to a first plasmatreatment. The plasma is formed in an ambient with oxygen, nitrogen,fluorine, argon, helium, another noble gas, or any combination thereof.A portion of the second conductive layer can react to form an aluminumoxide compound, aluminum nitride compound, aluminum fluoride compound,or any combination thereof.

A first additional conductive layer of Al, Ta, Nb, Ti, Zr, Hf, Ni, Co,Mo, W, La, Ce, other rare earth metals, In, Sn, Zn, an alloy of Ti—Zr,In—Sn, In—Zn, Al—Zn, or any combination thereof can be deposited byevaporation or sputtering under vacuum. The first additional conductivelayer can have a thickness in a range of approximately 5 nm toapproximately 100 nm. The surface of the first additional conductivelayer can be exposed to a second plasma treatment similar to the firstplasma treatment such that substantially all of the additionalconductive layer can be converted to a metallic oxide compound, metallicnitride compound, metallic fluoride compound or any combination thereof.

In other embodiments, other additional layers can be deposited andconverted to compounds using other plasma treatments. Any otheradditional conductive layer and any other plasma treatment can formother compound layers either the same or different from the firstadditional conductive layer.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, references to values stated in ranges include each and everyvalue within that range.

1. An electronic device, comprising: an organic active layer; and anelectrode further comprising: a first layer that is conductive; a secondlayer that is conductive, wherein the second layer includes a defectextending at least partly through a thickness of the second conductivelayer; and a third layer lying within and substantially filling thedefect, wherein each of the second and third layers comprise a samemetallic element.
 2. The electronic device of claim 1, furthercomprising another electrode wherein the organic active layer liesbetween the electrodes.
 3. The electronic device of claim 1, wherein thefirst conductive layer comprises a Group 1 metal, a Group 2 metal, orany combination thereof.
 4. The electronic device of claim 1, whereinthe second conductive layer comprises aluminum, silver, copper,chromium, or any combination thereof.
 5. The electronic device of claim1, wherein the third layer comprises a nitrogen-containing,oxygen-containing, fluorine-containing or any combination thereofmaterial.
 6. The electronic device of claim 1, wherein the electrodefurther comprises a fourth layer overlying the third layer, the fourthlayer including a metallic oxide compound, a metallic nitride compound,a metallic fluoride compound or any combination thereof.
 7. A processfor forming an electronic device comprising: forming an organic activelayer; forming an electrode further comprising a first layer and asecond layer, wherein: each of the first and second layers isconductive; the second layer is a last layer formed when forming theelectrode; and the second layer includes a defect extending at leastpartly through a thickness of the second layer; and exposing the secondlayer to a plasma to form a compound in the defect, wherein the compoundis formed from a portion of the second layer.
 8. The process of claim 7,wherein forming the organic active layer comprises continuously printingthe organic active layer.
 9. The process of claim 7, wherein forming theelectrode further comprises forming each of the first and second layersof the electrode using a physical vapor deposition process.
 10. Theprocess of claim 7, wherein forming the electrode further comprisesforming each of the first and second layers of the electrode using asame stencil mask.
 11. The process of claim 7, wherein the plasmaincludes oxygen, nitrogen, fluorine, argon, helium, another noble gas,or any combination thereof.
 12. The process of claim 11, wherein theplasma of the plasma treatment process is formed in anitrogen-containing, oxygen-containing, fluorine-containing or anycombination there of ambient.
 13. A process for forming an electronicdevice comprising: forming an organic active layer; forming a firstlayer that is conductive and is part of an electrode; forming a secondlayer; and exposing the second layer to a first plasma to form a firstcompound from the second layer, wherein substantially all of the secondlayer is consumed when forming the first compound.
 14. The process ofclaim 13, wherein the first plasma includes nitrogen, oxygen, fluorine,argon, helium, another noble gas, or any combination thereof.
 15. Theprocess of claim 13, wherein each of the first and second layerscomprise a metal-containing material.
 16. The process of claim 13further comprising forming a third layer after forming the first layerand before forming the second layer, wherein the third layer isconductive and is part of the electrode.
 17. The process of claim 16,further comprising forming a fourth layer after exposing the secondlayer to the first plasma.
 18. The process of claim 17, wherein thefourth layer includes a metal-containing layer.
 19. The process of claim18, further comprising exposing the fourth layer to a second plasma toform a second compound from the fourth layer, wherein substantially allof the fourth layer is consumed when forming the second compound. 20.The process of claim 13, wherein forming the second layer comprisesdepositing a material including aluminum, tantalum, niobium, titanium,zirconium, hafnium, nickel, cobalt, chromium, molybdenum, tungsten,lanthanum, cerium, another rare earth metal, indium, tin, zinc, an alloyof titanium and zirconium, indium and tin, indium and zinc, aluminum andzinc or any combination thereof.